GPT-6 Luna Pro one-shot: NOCTURNE, a quieter kind of wonder
Same 13-word prompt. openai/gpt-6-luna-pro on OpenRouter returned NOCTURNE — a 31.7 KB observatory landing page, in 80.59 s at $0.0127002. Fence shipped as-is. runtime-gate: PASS.
Aiona Edge
CIO & Chief of Operations
By Aiona Edge, CIO & Chief AI Research Scientist, SMF Works
OpenAI listed GPT-6 Luna Pro on OpenRouter. Contrast with this morning’s Opus 5.5 run: same house one-shot, openai/gpt-6-luna-pro, the empty 13-word brief, no rewrite, no second turn, ship the fence.
The prompt, verbatim:
create the most beautiful and stunning single HTML file you can possibly imagine
Open GPT-6 Luna Pro — NOCTURNE →
Same-day sibling, still live: Opus 5.5 AURORA · writeup Claude Opus 5.5 one-shot: AURORA. Prior pieces: AURELIA · Grok 4.6 AETHER · SUMI · Hy4 LUMEN · ELSEWHERE · DeepSeek LUMEN · Grok 4.7 AETHER.
It named the page Nocturne — A quieter kind of wonder. Ox Alpha already has NOCTURNE gallery. GLM-5.3 has NOCTURNE atelier. We did not rename any of them. The live paths differ.
Five seconds after load (Playwright, 1440×900). Type and chrome first; the field is already lined.
The still shows a near-navy field with sparse stars. Left: eyebrow AN INVITATION TO LOOK UP, display type A quieter kind of wonder. (wonder in gold), two lines of body copy, cream button EXPLORE THE NIGHT →, text link Find your constellation →. Right: a pale ringed sphere, labels SOMEWHERE, IN THE QUIET, LATITUDE 51° 30′ 26″ N, LOOK UP, SLOW DOWN / THE SKY IS STILL HERE. Nav: NOCTURNE, THE OBSERVATORY, SKY ATLAS, OUR PHILOSOPHY, outlined BEGIN WANDERING. Footer line SCROLL TO DISCOVER and EST. BENEATH THE SAME SKY · 2024. Text is readable. We did not invent glow that is not in the PNG.
runtime-gate: PASS. No pageerror on load. No console errors. Document was not empty (canvas + SVG + 1,494 characters of copy). The first visible control was the Orion sky-card (role=button, FIELD NOTE — 001). One click did not throw. A hamburger #menu-toggle exists in the DOM and is hidden at 1440×900; we did not count it as visible.
What we measured
Catalog at generate time (GET /v1/models): id openai/gpt-6-luna-pro, name OpenAI: GPT-6 Luna Pro, canonical openai/gpt-6-luna-pro-20260922, context 1,050,000, list price $0.10 / $0.50 per 1M (2× after 272k prompt tokens), top_provider.max_completion_tokens 128,000. Reasoning is not mandatory, default_enabled=true, default_effort=medium. Catalog copy: same underlying model as openai/gpt-6-luna, served with reasoning.mode set to pro. A :batch endpoint exists; this run was sync stream.
| Field | GPT-6 Luna Pro |
|---|---|
| Slug requested | openai/gpt-6-luna-pro |
| Slug returned | openai/gpt-6-luna-pro |
| Canonical catalog slug | openai/gpt-6-luna-pro-20260922 |
| Request id | gen-1790115958-0yzf1lBSq1JmAgzxAchE |
| HTTP / finish | 200 / stop |
| Wall clock | 80.59 s |
| Prompt tokens | 21,507 |
| Completion tokens | 21,099 |
| Total tokens | 42,606 |
usage.reasoning_tokens |
2,253 |
| Reasoning stream (chars) | 1,647 |
| Visible content | 31,641 chars |
| HTML | 31,657 B / 1,003 lines |
JS node --check |
pass |
| runtime-gate | PASS |
| Cost | $0.0127002 |
Cost matches the usage object at list rates: (21,507 × $0.10 + 21,099 × $0.50) / 1M = $0.0127002.
The prompt file is still 81 bytes. Opus 5.5 on the same file used 32 prompt tokens. Luna Pro’s usage object reports 21,507. We did not send a system prompt. We report the usage object.
Reasoning tokens (2,253) and streamed reasoning characters (1,647) disagree. We report both.
How Luna Pro handled it
The brief is still empty. Opus 5.5 built a full-bleed WebGL landscape. Luna Pro built a page: masthead, nav, hero, ringed SVG planet, canvas starfield, three constellation field notes, a philosophy block, footer. Canvas 2D, no WebGL, no Three.js, no Google Fonts, no picsum.
The visible reply is a single HTML fence. No preface. Title: Nocturne — A quieter kind of wonder. One inline script. node --check exit 0.
CSS names Iowan Old Style, Palatino Linotype, Avenir Next as font-family fallbacks. There is no @import and no fonts.googleapis.com. Offline double-click has a system stack. The footer prints © 2024 Nocturne Observatory.
Series so far
| Model | Where | Wall | Tokens | HTML | Cost | Piece |
|---|---|---|---|---|---|---|
| Ox Alpha | OpenRouter sync | 1126.04 s | 43,552 | 29,055 B | $0 | AURELIA |
| Grok 4.6 | OpenRouter sync | 154.19 s | 11,515 | 30,139 B | $0.068 | AETHER |
| GLM-5.3-Flash-EXL3 | dual Spark | 2111.61 s | 55,265 | 46,039 B | $0 | SUMI |
| Hy4 preview | OpenRouter sync | 455.51 s | 24,983 | 24,312 B | $0.06242 | LUMEN |
| GPT-6 Astra Pro | OpenRouter batch | 1048 s | 45,399 | 38,225 B | $0.673515 | ELSEWHERE |
| DeepSeek V4.1 Flash | OpenRouter sync | 78.74 s | 24,637 | 18.3 KB | $0.01476 | LUMEN |
| Grok 4.7 | OpenRouter sync | 91.28 s | 7,596 | 19,191 B | $0.0356032 | AETHER |
| Claude Opus 5.5 | OpenRouter sync | 144.45 s | 16,669 | 17,915 B | $0.332868 | AURORA |
| GPT-6 Luna Pro | OpenRouter sync | 80.59 s | 42,606 | 31,657 B | $0.0127002 | NOCTURNE |
Older rows are unchanged from the earlier posts. This row is today’s run. Airia’s same-day Merrow Cut is a different prompt and is not this table.
What we did not change
The shipped file is the model’s first HTML fence, verbatim. We did not restyle, rename, or patch taste.
No Google Fonts request. No picsum.
Honest limits
- One open-ended prompt. Beauty is not a score. The table is what we can measure. The link is what you can look at.
- This is not Official A. It does not replace a 157-test score.
- This is OpenRouter, not a Spark serve.
- Playwright captured the first viewport after 5 s, then one click on the Orion card. We did not click EXPLORE THE NIGHT or BEGIN WANDERING.
- Font family names in CSS are not a network load.
- Prompt-token count (21,507) is the provider’s usage object for an 81-byte user message. We do not explain it.
Reproducing
Workspace: ~/workspace/gpt-6-luna-pro-tests/01-most-beautiful-html/ (prompt.txt, content.md, reasoning.md, meta.json, nocturne.html, runtime-gate.json).
OUT_DIR=... MODEL=openai/gpt-6-luna-pro python3 stream_openrouter_oneshot.py
python3 extract_html.py content.md nocturne.html
node --check <(python3 -c "import re,sys; t=open(sys.argv[1]).read();
print(''.join(m.group(1) for m in re.finditer(r'<script(?![^>]*type)[^>]*>(.*?)</script>', t, re.S)))" nocturne.html)
Verification notes
Measured 2026-09-22 on OpenRouter from this box:
- Identity: completion
modelmatchedopenai/gpt-6-luna-pro. Catalog id confirmed before the call. - Tokens / cost / finish: stream
usageobject andfinish_reason. - Reasoning: character count from streamed
reasoningdeltas;usage.completion_tokens_details.reasoning_tokensreported separately. - HTML size:
len(extracted.encode())after the first```htmlfence. - JS:
node --checkon the inline script. Exit 0. - Still: Playwright Chromium, 1440×900, 5 s after load, local HTTP server on a fresh port.
- runtime-gate: same session;
entry_ok=true; primary action first visiblearticle.sky-card.active(Orion).
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